Adjustable support for ring drilling

ABSTRACT

THE PRESENT INVENTION CONCERNS A RING DRILLING DEVICE ADAPTED FOR OPERATING IN A TUNNEL AND COMPRISING A BOOM ROTATING ABOUT ITS LONGITUDINAL AXIS AND TO WHICH IS ATTACHED A CRADLE TRANSVERSE THERETO FOR THE FEEDING DEVICE FOR THE ROCK DRILL. ON THE ROTATABLE BOOM, THERE IS MOUNTED A BOOM HEAD TURNABLE ABOUT AN AXIS PERPENDICULAR TO SAID BOOM, THE CRADLE BEING MOUNTED ON THIS TURNABLE BOOM HEAD TO BE ROTATABLE ABOUT IS LONGITUDINAL AXIS.

Nov. 7, 1972 T. GRONFORS 3,702,162

ADJUSTABLE SUPPORT FOR RING DRILLING Filed Dec. 15, 1970 v 3 Sheets-Sheet l Nov. 7, 1972 T. GRONFORS 3,702,162

ADJUSTABLE SUPPORT FOR RING DRILLING Filed Dec. 15, 1970 Q13 5 SheetsSheet 2 :ll' I i AWA /KWAWN Nov. 7, 1972 T. GRONFORS ADJUSTABLE SUPPORT FOR RING DRILLING 3 Sheets-Sheet 5 Filed Dec. 15, 1970 United States Patent 3,702,162 ADJUSTABLE SUPPORT FOR RING DRILLING Teuvo Gronfors, Tampere, Finland, assignor to 0y Tampella AB, Tampere, Finland Filed Dec. 15, 1970, Ser. No. 98,380 Claims priority, application Finland, Oct. 19, 1970, 2,811 Int. Cl. E21c 11/02 US. Cl. 173-43 ABSTRACT OF THE DISCLOSURE The present invention concerns a ring drilling device adapted for operating in a tunnel and comprising a boom rotating about its longitudinal axis and to which is attached a cradle transverse thereto for the feeding device for the rock drill. On the rotatable boom, there is mounted a boom head turnable about an axis perpendicular to said boom, the cradle being mounted on this turnable boom head to be rotatable about is longitudinal axis.

This invention relates to ring drilling devices.

Ring drilling means that form a previously bored tunnel there are drilled, with the aid of extension steels, long radial holes which may have for example a length of up to several tens of meters, for the purpose of blasting a vertical slab off the rock in which the tunnel is dulled. The device according to the invention is exclusively intended for such ring drilling and not for example, for tunnel drilling.

Ring drilling is often carried out in such manner that the holes which have a horizontal or downward direction are drilled in one plane, which is vertical. On the other hand, those holes which have an upward direction are also drilled in one plane, but this plane deviates, for instance, 30 degrees from the vertical. This has the effect that the rock is more easily detached when the explosive placed in the holes is detonated. Since the upwardly directed holes lie in a plane, all holes to not have the same inclination. The inclination of holes closer to the horizontal plane is less than that of holes at a greater distance from the horizontal plane. The inclination of the holes varies from 0 to 30 degrees. When using ring drilling devices belonging to prior art, one must for every hole located above the horizontal "plane calculate in advance the central angle, or polar angle, and the angle of inclination. Furthermore, at drilling the drill steel has to be aligned in consideration of both these angles, before the drilling of the hole is commenced. Such calculation of the hole direction and aligning of the drill steel is awkward.

An object of the present invention is to provide a ring drilling device by the use of which, when inclined holes are drilled, all holes will automatically lie in one plane. The invention is characterized in that on a rotatable boom there is mounted a boom head turnable about an axis perpendicular to the boom and that a cradle is mounted on this turnable boom head to be turnable about its longitudinal axis.

If it is desired to drill with a ring drilling device according to the invention, holes which lie, for example, in a plane with 30 degrees inclination, it is merely necessary to turn the boom head so that its axis encloses with the axis of the boom an angle of 30 degrees. All holes will then automatically be in the same plane, having an inclination of 30 degrees, when the cradle is turned step by step about the boom head on transfer from hole to hole.

It is sometimes desired to form the ring of holes so that the holes constitute a conical surface. This is possible according to the invention simply by turning the boom head so that its axis encloses an angle with the axis of the boom. All holes will then automatically lie on a conical 3 Claims surface when the boom is turned step by step about its longitudinal axis, at transition from hole to hole. Up to date no ring drilling device has been known by means of which it is possible to drill all of the above-mentioned kinds of hole rings, that is sets of holes located in a vertical plane or in an inclined plane or in a plane placed at an oblique angle to the longitudinal axis of the tunnel. or on a conical surface.

Special instances occur in ring drilling, for instance, when the tunnel from which the ring drilling is performed is inclined in one direction or in the other or when the tunnel has an oblique course with reference to the rock or ore body to be blasted. In all these special instances the device according to the invention is excellently appropriate, while devices belonging to prior art are only poorly suitable or not at all.

The invention is described more closely in the following with the aid of an example and with reference to the attached drawings, wherein:

FIG. 1 shows, in perspective and in cross section view, an ore body which is to be blasted.

FIG. 2 is an end view of a carriage on which two ring drilling devices according to the invention have been mounted;

FIG. 3 shows the same carriage in elevational view from one side;

FIG. 4 shows, on an enlarged scale and partly in section, a ring drilling device according to the invention;

FIG. 5 shows the same ring drilling device, viewed from about and partly in section.

FIG. 1 demonstrates what is meant by ring drilling. Into the ore body 1 within the ground there have been, in advance, run tunnels 2, 3, 4 and 5 at different levels. Furthermore, below the tunnel 2 conical drop tunnels 6 have been made, which open into transverse transport tunnels 7, which in their turn open into longitudinal transport tunnels 8. The ring drilling is commenced from the tunnel 2. With the aid of a device according to the invention a ring of radial holes is drilled, hole by hole. The holes 9 directed horizontally or downwardly lie in a plane which is vertical, while the holes 10 inclined above the horizontal plane lie in a plane which has 30 degrees inclination in the direction which has already been blasted. After the ring of holes 9 and 10 has been completed, the holes are charged with explosive, which is detonated, whereby a slab-shaped area is detached from the ore body and falls into the drop tunnels 6, and further into the transverse transport tunnels 7, after which the ore particles are transferred into the longitudinal transport tunnels 8 and further to the winding pit. In this manner, working from the tunnel 2 continues, whereafter similar procedures are instituted from tunnels 3 and 4 and, finally, from tunnel 5.

FIGS. 2 and 3 show a carriage provided with bogie wheels 11 and on which have been mounted two ring drilling devices according to the invention, so that simultaneousely two ring sets of holes, spaced in the longitudinal direction of the tunnel, can be drilled. The carriage can be braced against the sole of the tunnel by means of stays extruding from pressure cylinders 12 and against the roof, by means of a stay extruding from pressure cylinder 13.

The ring drilling device on the right in FIG. 3 is more closely illustrated in FIGS. 4 and 5. The device consists of a boom 14, which is carried in journals 15 on the body of the carriage. The boom 14 is rotated by means of a turning cylinder, consisting of a housing 16 integrally connected with the body of the carriage and having in its interior a double-acting piston. The piston rod 17 is designed to be a tooth rack, which engages to toothed end 18 of the boom 14, which end projects into the housing 1 6. When a pressure medium is fed to one end or the other of housing 16, the piston moves accordingly, whereby the piston rod 17 formed to act as a tooth rack rotates the boom 14. The piston rod 17 has such length that it is able to rotate the boom 14 through 360 degrees.

a On the boom 14 there is mounted a boom head turnable about an axis 19 perpendicular to the boom and which is shaped to constitute a bell crank lever 20, 21. This bell crank lever can be turned 45 degrees in one direction or the other by the aid of pressure cylinder 22, which is connected, on one hand, to a lug .23 fixed to the boom 14 and, on the other hand, to the bell crank arm 21.

On the arm of the boom head shaped as a bell crank lever there is mounted a turning cylinder perpendicular to its axis, this cylinder being similar in principle to the turning cylinder 16 described in the foregoing. The housing 24 of the turning cylinder is journalled in the boom head 20.

1. The piston rod is designedto constitute a tooth rack, which engages the toothed segment 26. When pressure medium is supplied at one end or the other of the housing 24, the piston moves accordingly, whereby the piston rod 25 shaped to act as a tooth rack, forces the housing 24 to revolve about the boom head 20. The piston rod 25 has such length that the housing 24 may move through 360 degrees about the boom head 20.

-To the housing 24 is attached the cradle 27, which carries the feed device 29 of the rock drill 28, this feed device being movable in its longitudinal direction by means of the displacement cylinder 30. The feed device 29 carries at its end guiding jaws 31 for the drill steel attached to the rock drill 28. 'In FIGS. 4 and 5 part of these elements have been omitted for the sake of clarity.

When ring drilling is being carried out, the carriage is so placed in the tunnel that the boom 14 will be parallel to the longitudinal axis of the tunnel, and the carriage is locked in its place with the aid of pressure cylinders 12 and 13. If holes lying in a vertical plane are drilled, the boom head 20 is set with the aid of cylinder 22 to be in-a position in which its axis is horizontal. It is then totally immaterial whether the base on which the carriage rests is level, or whether or not the axis of the boom 14 is horizontal. The holes are now drilled by advancing the turning cylinder 24 step by step about the boom head 20, at transition from hole to hole.

. If it is desired to drill such holes which are located in one inclined plane, the boom head 20 is adjusted with the aid of cylinder 22 to assume a position in which its axis is perpendicular to this inclined plane. Again, the holes are drilled, advancing the turning cylinder 24 step by step about the boom head 20, at transition from hole to hole.

In the event that one desires to drill holes lying on a conical surface, the axis of the boom 14 is aligned to be parallel to the axis of this cone, and with the aid of cylinder 22 the turning cylinder 24 is adjusted to be 4 parallel to the side line of the cone. The holes are now drilled, advancing with the aid of turning cylinder 16 the angular position of the boom 14, step by step, at transition from hole to hole.

With a device according to the invention all the drilling operations required in ring drilling can be performed, making use of the cylinder 22 and of the turning cylinders 16 and 24. The performance of the device is augmented by the fact that the range of operation of both turning cylinders covers a full circle.

It is clear to anyone skilled in the field that various embodiments of the invention may vary within the scope of the attached claims. For instance, the device turning the boom 14 and the device turning the cradle 27 need not necessarily be turning cylinders, but, for example, electric, hydraulic or pneumatic motors may also be considered. However, turning cylinders are advantageous in the respect that by their aid the boom 14 and on the other hand the cradle 27 can be locked exactly and, with permanent accuracy, in the right angular positions.

I claim:

1. A ring drilling device adapted for operating in a tunnel, comprising a rock drill, a boom having and rotatable about a longitudinal axis, a cradle transverse to said boom, a feed device in said cradle for the rock drill, a boom head mounted and turnable on the rotatable boom about an axis perpendicular to said boom, the cradle being mounted on said turnable boom head to be rotatable about its longitudinal axis, and turning cylinders, said boom being arranged to be rotatable about its longitudinal axis with the aid of one said turning cylinders, the cradle being arranged to be turnable about the longitudinal axis of the boom head with the aid of one of said turning cylinders.

2. A ring drilling device according to claim 1, wherein the turnable boom head includes a bell crank lever including an arm comprising a pressure cylinder between said arm and the boom for turning the boom head.

3. A ring drilling device according to claim 2, wherein the first turning cylinder is a cylinder which is adapted to turn the boom through at least 360 degrees, and the second turning cylinder is a cylinder which is adapted to turn the cradle through at least 360 degrees.

References Cited UNITED STATES PATENTS 3,218,893 11/1965 Madison et a1 l7338 X 3,470,969 10/1969 Arcangeli l7343 2,750,155 6/1956 Nixon 24816 X ERNEST R. PURSER, Primary Examiner U.S. Cl. X.R. l7352; 24816 

